The present invention relates generally to ice making apparatus and methods of making ice, and in particular to such apparatus and methods in which ice is formed on a plurality of vertically oriented and parallel evaporator tubes.
There have been various attempts to make pieces of ice by forming an elongated section of ice and then somehow fracturing the ice section to form pieces which may or may not resemble ice "cubes", which are generally thought of as being formed individually, oftentimes in individual cavities. Such apparatus is to be distinguished from continuous apparatus for making shaved ice or the like, which operates on somewhat different principles and produces soft ice.
U.S. Pat. No. 3,984,996 discloses an icemaker which freezes a vertical tube of ice of square cross section, and employs a central rotating shaft to drive the frozen tube upward. The apparatus is designed for continuous operation in a compartment of a home freezer, and has a pair of synchronized blade-type cutters at the top to fracture the slowly upwardly moving tube of ice into cube-like sections. U.S. Pat. Nos. 2,595,588 and 3,287,927 also disclose ice making machines which intermittently freeze a vertical column of ice and then eject the frozen column slowly upward to a breaking mechanism for fracturing the emerging column into pieces at an upper location. None of these designs has proven to be entirely satisfactory.
According to U.S. Pat. No. 4,429,543 to Fischer, assigned to the assignee of the present invention, a helix of ice is formed by circulating a refrigerant through the interior of a helical evaporator tubing section, while water is supplied to the exterior of the evaporator, preferably by immersion. Upon achievement of a desired thickness of ice, the supply of regfrigerant is discontinued and the evaporator is heated to break the ice bond. A driver is then actuated to rotate the ice helix slidably upon and along the helical evaporator, and to cause the leading edge of the ice helix to fracture upon reaching a length of tubing disposed at an angle from the regular curvature of the evaporator. The icemaker is very efficient in that, for a given size, it is capable of manufacturing relatively large quantities of ice within relatively short periods of time. However, efforts continue to be made to maximize the quantities of ice that may be produced by an icemaker of given size.